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Brake bleeding – Mityvac MV8500 silverline elite aUtoMotive test kit User Manual

Page 24

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BENCH BLEEDNG THE MASTER CYLINDER

Whenever a master cylinder has been removed

from a vehicle or a new one is being installed,

the master cylinder must be bench bled . Failure

to bench bleed is the main reason for unsuccess-

ful master cylinder replacement . Bench bleeding

greatly decreases the chance that any air will

be caught in the cylinder upon reinstallation .

Follow this procedure:
1) Plug outlet holes of the master cylinder and

gently clamp it in a vise with the push rod end

slightly elevated . NOTE: Damage may result if

master cylinder is clamped by the bore or if

reservoirs are clamped too tightly .
) Fill the master cylinder with an approved type

brake fluid and keep it filled at all times during

the procedures .
3) Remove a plug from the master cylinder and

attach the proper adapter to this master cylinder

outlet port . Connect the pump tube to the reservoir

jar and the jar tube to the adapter (FIGURE 19) .

4) Operate the pump and observe air and fluid

flowing into the reservoir until clear, bubble-free

fluid appears .
5) Plug the outlet tightly and repeat step 4 on the

other outlet ports .
6) Clamp master cylinder in a vise with the push rod

end down slightly . Slowly slide the master cylinder

push rod back and forth about

1

8

”, until no air

bubbles can be seen in the reservoirs .
7) Remount the master cylinder with the push rod

end up and follow steps 3 & 4 on all outlet ports .

Plug ports tightly . The master cylinder is now free

of air and ready to install .

braKe bLeeDinG

FIGURE 19: BENCH BLEEDING

Page Number - 4

Form 8433